Method and apparatus for conversion of cellulosic material to ethanol

Abstract

The present invention provides an apparatus and a method for conversion of cellulosic material, such as chopped straw and corn stover, and household waste, to ethanol and other products. The cellulosic material is subjected to continuous hydrothermal pre-treatment without addition of chemicals, and a liquid and a fiber fraction are produced. The fiber fraction is subjected to enzymatic liquefaction and saccharification. The method of the present invention comprises: performing the hydrothermal pre-treatment by subjecting the cellulosic material to at least one soaking operation, and conveying the cellulosic material through at least one pressurized reactor, and subjecting the cellulosic material to at least one pressing operation, creating a fiber fraction and a liquid fraction; selecting the temperature and residence time for the hydrothermal pretreatment, so that the fibrous structure of the feedstock is maintained and at least 80% of the lignin is maintained in the fiber fraction.

The invention claimed is: 
     
       1. An apparatus for the treatment of cellulosic material, said apparatus comprising:
 a first pressurized reactor section comprising a reactor pressure zone configured to operate at an elevated pressure; 
 a separation device attached to the first pressurized reactor section, wherein said separation device is configured to create a fibre fraction and a liquid fraction from the cellulosic material, wherein said separation device is a pressing device; 
 a discharge device capable of discharging the fibre fraction from the first pressurized reactor section to a second pressurized reactor section operable at a lower pressure than the first pressurized reactor section; 
 a liquid fraction unloading mechanism configured to unload the liquid fraction from the first pressurized reactor section to a closed collection zone; and 
 a closed collection zone configured to receive the liquid fraction from the first pressurized reactor section through the unloading mechanism. 
 
     
     
       2. The apparatus of  claim 1 , wherein said liquid fraction unloading mechanism comprises a sluice device for removal of liquid following discharge after the first pressurized reactor section. 
     
     
       3. The apparatus of  claim 1 , wherein said separation device is a screw press. 
     
     
       4. The apparatus of  claim 1 , further comprising a cleaning device configured to clean the the cellulosic material, attached upstream of said first reactor section. 
     
     
       5. The apparatus of  claim 1 , further comprising a soaking apparatus attached upstream of the first pressurized reactor section. 
     
     
       6. The apparatus of  claim 5 , wherein a separation device is attached between the soaking apparatus and the first pressurized reactor section. 
     
     
       7. The apparatus of  claim 1 , wherein the first pressurized reactor section and the second pressurized reactor section are in separate zones of a single reactor. 
     
     
       8. The apparatus of  claim 1 , wherein the first pressurized reactor section and the second pressurized reactor section are in separate reactors. 
     
     
       9. The apparatus of  claim 1 , further comprising a means for counter current cooling of the fibre fraction after the first pressurized reactor section. 
     
     
       10. The apparatus of  claim 1 , further comprising an ethanol fermentation device attached downstream of the second pressurized reactor section for fermentation of the separated liquid fraction. 
     
     
       11. An apparatus for the treatment of lignocellulosic material, said apparatus comprising:
 a first pressurized reactor section comprising a reactor pressure zone at an elevated pressure and comprising a lignocellulosic biomass; 
 a separation device attached to the first pressurized reactor section, wherein said separation device is configured to create a fibre fraction and a liquid fraction from the lignocellulosic material, wherein said separation device is a pressing device; 
 a discharge device configured to discharge the fibre fraction from the first pressurized reactor section to a second pressurized reactor section, wherein the second pressurized reactor section is at a different pressure than the first pressurized reactor section; 
 a liquid fraction unloading mechanism configured to unload the liquid fraction from the first pressurized reactor section to a closed collection zone; and 
 a closed collection zone configured to receive the liquid fraction from the first pressurized reactor section through the unloading mechanism. 
 
     
     
       12. The apparatus of  claim 11 , further comprising a soaking apparatus attached upstream of the first pressurized reactor section. 
     
     
       13. The apparatus of  claim 11 , wherein the first pressurized reactor section and the second pressurized reactor section are in separate zones of a single reactor. 
     
     
       14. The apparatus of  claim 11 , further comprising an ethanol fermentation device attached downstream of the second pressurized reactor section for fermentation of the separated liquid fraction.